1. Field of the Invention
The present invention relates to a unit of piezoelectric element preferably used as a part of driving unit for driving a driven element.
2. Description of the Related Art
The piezoelectric element is an element, which mutually transforms between mechanical displacement and electric displacement by using piezoelectric effect and inverse piezoelectric effect. Such piezoelectric elements are manufactured e.g. by forming and firing a piezoelectric ceramic to obtain element body, forming electrode thereto, and further performing polarization treatment.
The mechanical displacement caused by the piezoelectric element is relatively small; and that the piezoelectric element is suitably used for such as a driving unit in which accuracy and exactness is required. In concrete, it is used for such as a lens driver, a head driver of HDD, a head driver for ink-jet printer, a fuel injection valve driver, and the like.
For instance, as a driving unit using piezoelectric element, a structure wherein a driving rod and a support are respectively connected to both ends of piezoelectric element is described (See Patent Article 1: Japanese Laid-Open Patent Publication No. 2002-119074).